New peatland construction methods could unlock further rural housing developments

A new study is being carried out into more environmentally friendly methods for laying housing foundations on peatland that could pave the way for increased economic development in parts of the Highlands and Islands, while mitigating disruption to the natural ecosystem and captured carbon dioxide.

New peatland construction methods could unlock further rural housing developments

A research consortium involving Edinburgh Napier University and Heriot-Watt University, with support from the Highland Council, Highlands and Islands Enterprise (HIE), Construction Scotland Innovation Centre (CSIC) and JAHAMA Highland Estates is assessing the feasibility of a range of construction methods to minimise disturbance to peat and mitigate the environmental impacts. The Scottish Environment Protection Agency (SEPA), NatureScot, ECOSystems Tech Ltd and the Scottish Government are also supporting the initiative.

Peatland plays an important role in Scotland’s natural landscape and ecosystem, comprising of dead and decaying plant material with carbon captured in the remains. As much as 20% of Scottish land is covered in peat soil serving as a significant carbon store for more than 1.7 billion tonnes of carbon - equivalent to 140 years’ worth of Scotland’s total annual greenhouse gas emissions. However, the soil is often unsuitable for building upon because of low strength, landslide risks and its tendency to deform under load.

In parts of the Highlands and Islands, where peatland is commonly found, new housing is in short supply and some sites earmarked for housing development can be complicated by the presence of peat. Finding viable, sustainable methods for building on peatland that align with restoration work already underway, could transform Scotland’s approach to rural housing. Good quality, affordable homes could help to reverse population decline and promote economic growth in rural areas, encouraging a young and talented workforce to move to, and remain in, the Highlands and Islands.

Construction teams have previously relied on excavate-and-replace techniques, however, this project will explore a number of options that allow peat - and stored carbon - to be left in place, such as deep-soil-mixing, and piling. Timber piling would use tree trunks or long poles of timber to carry the foundations of a building. Disturbance of the peatland would be minimised, especially the presence groundwater, which is essential if peat is to continue to accumulate.

The aim of the first phase of the project is to assess and compare the geotechnical suitability, environmental impact, logistics and cost implications of the different approaches. In a second phase, live field trials are planned to assess the suitability of proposed solutions.

Councillor Trish Robertson, chair of the council’s economy and infrastructure committee at Highland Council, said: “Highland Council is happy to support this research project as a way of exploring innovative ways of achieving our objectives of delivering more affordable housing and inclusive economic growth, while safeguarding better croft and other agricultural land, and reducing the carbon emissions presently caused by development on poorer agricultural land, which often contains significant peat deposits. I am hopeful that the results of the research can have a practical application for future developments and help us even better achieve our objectives.”

Julia Stoddart, chief operating officer at Jahama Highland Estates, said: “Preserving and restoring peatland to keep carbon sequestered and enhance biodiversity is central to the land management work happening right now across JAHAMA Highland Estates.

“With over 14,000ha of peatland on the estate, restoration work forms a significant part of our parent organisation GFG Alliance’s efforts to offset the carbon footprint of its industrial operations as it progresses towards carbon neutrality by 2030.

“As a large employer in the local area, GFG Alliance also recognises the importance of this research in addressing the long-standing issues concerning housing stock in the Highlands. We are committed to reconnecting people and place in Lochaber and Badenoch. Releasing constrained land for sustainable new housing would be transformative for our local communities.”

Scott Dingwall, head of regional development, Lochaber, Skye and Wester Ross, at Highlands and Islands Enterprise, said: “The availability of suitable affordable housing is a key factor in regional development across the Highlands and Islands. It is needed to attract and retain young people as well as inward investors looking to locate in the region. This innovative project has the potential to make it feasible to develop housing on areas where it previously would not have been considered.

“This could benefit rural economies and strengthen local communities, while protecting some of the region’s outstanding natural features. As such, it could be a key element in our shift towards a carbon neutral economy and achieving our net-zero targets. We are very pleased to be able to provide support and look forward to seeing the project progress.”

Dr John McDougall of Edinburgh Napier University said: “Peatland has long posed a challenge to construction, the solution to which has commonly been an aggressive practice of removal. More recently, planners, environmental agencies and engineers have become increasingly aware of the very significant role of intact peat in the carbon cycle. In this context, it is exciting to be leading a re-evaluation of foundation options in the context of geotechnical, environmental and economic factors.”

Andrew Nurse, project manager at CSIC, added: “In line with Scotland’s goals for net-zero, especially in the construction sector, we are looking at more sustainable options such as timber piles, as a solution for building on peatland - which could also make use of local, home-grown materials. Once we have reached conclusions from the feasibility study, the next stage will be to conduct a series of on-site trials at various locations in the Highlands and Islands.”

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